Solid solution strengthening in polycrystals of Mg–Sn binary alloys

Solid solution effects on the hardness and flow stress in Mg–Sn binary alloys with Sn content between 0.18% and 2.18% at temperatures ranging from ambient to 623 K were investigated in this study. At room temperature, the hardness increases with the Sn content as Hv0.5 = 28.3 + 6.88c, the 0.2% proof strength (corrected for grain size strengthening effect) and cn follow a linear relationship, where c is the solute atom fraction and n = 1/2 or 2/3. The results suggest that the strengthening of basal planes controls the solid solution strengthening in polycrystals of Mg–Sn binary alloys. However, the cn power-law is not applicable in the temperature range from 423 K to 623 K, which is proposed to be ascribed to the competition between solid solution strengthening and softening effect.

Research highlights▶ The 0.2% proof strength for the polycrystals of Mg–Sn binary alloys increases linearly with cn at room temperature, where c is the solute Sn atom concentration and n = 1/2 and 2/3. ▶ It is suggested that the strengthening of basal planes controls the solid solution strengthening effect in polycrystals of Mg–Sn binary alloys. ▶ The cn power-law is not applicable in the temperature range 423–623 K, which is explained by the occurrence of the softening effect.